I have seen this as well with the two Titan 425's I have. Seeing a fix
here would be great! I love the amp....but would love to see the tuning
more in the "mid-range" of the tune sweep.
Thanks...
Rich
-----Original Message-----
From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]
On Behalf Of Gary Myers
Sent: Thursday, December 21, 2006 8:07 AM
To: amps@contesting.com
Subject: Re: [Amps] Pi-L Tank on TenTec Titan 425
Help!
I have a nice Titan - works great for the most part even with a
20 year old tube... however on 10 meters the "peak" on the tune
capacitor is right at the minimum capacitance point above about
28.1 Mhz. Is there anything I can do, simply, to raise this
just
enough to know I am tuned properly (i.e. requiring LESS
capacitance)?
I contacted TT service - they are a great bunch of people for
the most part... they said
I spoke to the RF design engineer. If the coil is expanded on
10
meters in
order to use more tune capacitance then the tuning will change
on 15 meters.
If the tuning is changed on 15 meters then the plate choke
might
be damaged.
The suck out frequency for the plate choke is near the 15 meter
band. As
long as the tune cap will resonate there is no problem.
My response was it does NOT resonate now - it is obvious it
needs less capacitance to do so... and that I can't imagine it
is THAT close and critical... finally something most be off to
begin with for it not to work as spec'd in their manual
(setting
in manual is 5% of capacitance). Of course I could change the
series cap, 25p to maybe a 20 but finding one might be
difficult
and getting it in more so... I could also parallel another high
value cap with the 25 but again space dictates this to be
difficult...I would love to know if I can spread (or compress?)
the 10 meter section of the coil and accomplish what I need.
The
SWR is around 1.2:1 - 1.3:1.
thanks for any help.
Gary
K9RX
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